The invention relates to a switching arrangement for rotating toothbrush.
It is known to provide a toothbrush which includes a rectangular housing in which an electromotor is arranged. Via a shaft, the motor drives a clutch shaft carrying the toothbrush wherein the housing accommodates a mercury gravity switch for reversing the direction of rotation of the motor. Furthermore, a manually actuatable switch is arranged outside the housing which provides a reversing of the rotational direction of the motor for treating the upper and lower jaw, wherein the reversing of the rotational direction of the electromotor for the treatment of the inner and outer side of the tooth is obtained through turning of the toothbrush around the longitudinal axis.
A rotating toothbrush with such an unconfusable switching arrangement is described in West German patent document 3,211,984. Through the one time operation of the manually actuatable switch, it is determined at the start of the tooth brushing whether the brushing should start with the teeth of the upper or the lower jaw. After this determination and the start of the brushing, the reversing for the right and left sides for the inner and outer side of the tooth is automatically obtained so that the brush provides continuously the correct rotational direction i.e., from the gums to the tooth that is from "red" to "white". For adjusting the correct rotational direction for the other part of the jaw, the switch is manually actuated so that the device is programmed for brushing the other half of the jaw. A correct switching of the manually actuatable switch can be confirmed by an optical indication or be obtained by sensing means or accoustic means or by any combination of these means. For left-handers, these indicating means are arranged in the opposite manner.
With the switching arrangement of the known rotating toothbrush, it is achieved effectively for the first time to control the non-interchangeability of the rotational directions by simple means.
A problem of all known rotating toothbrushes operating with a centrifugal switch resides in the duration of the reversing and above all in the response sensitivity upon tilting of the switch. With the switches used so far, a so-called "stammering" i.e., a momentary, frequent stopping of the rotational movement of the motor cannot be prevented upon rotation of the toothbrush along the longitudinal axis when the switching elements of the switch, disengaged from the contact and seek to engage the counter contact. The stammering impairs, however, the brushing of the teeth in a considerable manner because it cannot be recognized whether the toothbrush stammers or stops is caused by the switching process or by of a defect. Moreover, upon stammering of the toothbrush, the rotational direction can be altered so that even incorrect rotational directions (white to red) can occur.